Electrical system



D. E. SUNSTE IIN ELECTRICAL SYSTEM Nov. 20, 1945.

Filed Oct. 28. 1944 Patented Nov. 20, 1945 UNITED STAT S PATENT OFFICE David Elias Sunstein, Elkins Park, Pa., assignor to Philco Corporation, Philadelphia, Pa., a corporation Pennsylvania Application October 28, 1944, Serial No. 560,876

(Cl. 1-15 a2o) sure of contact II it pulls up its armature l3 and 11 Claims.

This invention relates to electrical control systems and has for its primary object to accomplish certain operational sequences with a minimum of equipment or, in any event, with less costly equipment than would otherwise be required.

That embodiment of the invention, hereinafter described, which has actually been put to use, forms a component portion of an automatic system for calibrating radio signal generators; but it is susceptible of being utilized profitably in other systems where similar operational sequence are required to be preformed.

The two additional embodiments shown in the drawing and described hereinafter have been included for the purpose of illustrating some of the practicable modifications within the scope and purview of my inventive concept, and which can usefulh! be-resorted to whenever the need may arise.

Referring to the drawing:

Fig. 1 is a circuit diagram oi a component portion of an automatic calibration system and illustrates an embodiment of the invention which is now in commercial use;

Fig. 2 is a circuit diagram illustrating an arrangement which is basically identical with that of Fig. l, but modified to meet a difierent operational requirement; and

Fig. 3 is a circuit diagram illustrating an arrangement which is fundamentally like that of Fig. 2, but entailing certain changes which may, in appropriate circumstances, advantageously be adopted.

In Fig. 1 there are shown two electric relays designated A and B, respectively. The prescribed requirement with respect to the functioning of Fig. 1 is that any operation of relay A,

closes a contact ll which completes a locking circuit through the winding of said relay. Thus, relay 3 is kept energized irrespective of the subsequent operation of contact II and remains energized pending a subsequent operation of relay A. And, as will presently be seen, it makes no difference whether the aforementioned subsequent operation of relay A is an actuation or deactuation thereof. That is to say, de-energization of relay B will result whether relay A pulls up or releases.

It will be observed that relay A has a back contact l5, shown closed, and a front contact i6, shown open; and each of said contacts is included, individually, in one of two parallel branch paths I1 and i8, including, respectively, condensers i9 and 20., Condenser I9 is shunted by a high leakage resistance 2i, and condenser 20 is similarly shunted by a high leakage resistance 22. It is possible to employ leaky condensers and thus eliminate resistors 2| and 22, but that is not considered good practice.

If contact III is closed, with contact l5 also closed, condenser Iii will be charged, first by way of resistance II and then via contact H, which closes immediately after closure of contact I0. Subsequently, upon opening of contact l5, condenser l9 discharges through resistor 2 i. Meanwhile, condenser 20 is without a charge-having been fully discharged through its shunt resistor 22. Hence, upon closureoi' contact l6, brought about by energization of relay A, a flow of current into condenser 20, via contact M, will cause a momentary diversion of current away from the winding of relay B-which diversion is sumcient to effect de-energization of relay B. The

consequent opening oi! contact it causes relay whether actuation or deactuation, must causev de-energization of relay B-pre-existing energizationof the latter being postulated. 4

There are several ways outside the scope of this invention by which the aiorestated result can be accomplished; but so far as I am aware, all such solutions of the problem involve either more or costlier equipment than does the arrangement of Fig. 1.

Initial actuation of relay B is effected by clos-' ing a contact III, which completes a circuit from a source of current through resistance ii and the winding of relay B to ground-at l2. Contact I0 is closed momentarily at intervals and may be actuated either manually, mechanically, or

electrically. A

when relay B is energized as a result of clo- B to remain de-energized until cont act in is again closed.

Following the actuation of relay A and the resultant opening of contact l5, condenser i9 discharges through its shunt resistor 2|, Just as condenser 20 had previously done while contact It was open. Hence, as will now be apparent, ii relay B is again actuated by closure of contact I 0,- it will, in turn, become deactuated upon deenergization of relay A and theresultant closure of contact l5.

Manlfestly, it is not of the essence of this invention that contacts ii and It be electroma netically actuated. They could as well be manually or mechanically actuated; andit should be apparent that there may be substituted in place oirelay 13 any electrical device, such as an electromagnetic step-by-step switch or an electric motor, or an electric heating element, provided such substituted device is operative, upon energization, to bring about closure or a locking circuit, and i capable of opening such circuit upon de-energization. v

It is to be understood that the element designated as relay B would ordinarily be equipped with additional contacts, not shown, for controlling one or more auxiliary circuits. But such a provision is, of course, not applicable unless the element in question is in fact a relay.

As will be evident, relay B can be energized by manually or mechanically closing contacts l4, thus permitting elimination of contact ill; but usually-contact i is located at a remote point and is, for that reason, needed.

The capacity requirements as respects condensers I9 and 20 obviously depend to a large extent upon the impedance of the winding of relay B. Generally these requirements are not critical except that the capacities must be large enough to bring about a decrease of the voltage across the relay winding of such degree and for a long,

enough time to insure the opening of contact M. Preferably these capacities should not be substantially greater than is found necessary in each specific case. Leakage resistances 2I- and 22 should be high enough to avoid excessive shorting of the condensers, but low enough to insure that the condensers will discharge adequately within whatever period of time may be allowable. The period, obviously, is a function of the frequency of operation of relay A.

In some cases it may be desirable to energize relay B in response to each operation of relay A, instead of de-energizing it in response to each such operation; and Fig. 2 illustrates a modification of Fig. I designed to bring about that alternative result. In the system of Fig. 2, each successive movement of the armature of relay A results in closing the previously open contact 15 or IE, with the result that an impulse of current flows from source 23 through resistance 24 and the winding of relay B via one of the condensers l9 or 20. This current impulse is effective to cause relay B to pull" up its armature, thus closing the locking contact I l. Relay B remains energized pending subsequent closure of contact 25, which puts ground on both terminals of the winding of relay B, causing the latter to release. Relay B can, of course, be replaced by any desired electrical device capable, upon energization, of closing a locking circuit.

In each of the two previously described embodiments of the invention it has been predicated that contacts [5 and [6 are, respectively, the back and front contacts of a relay A--in which case there apparently would never be need for more than two'parallel paths I1 and I8. Now I wish to po t out t at the invention is not limited movement oi. contactor 30 from one fixed contact to another will bring about energization of relay B, if the latter is not already energized.

Further description of Fig. 3 is not considered necessary in view of the fact that its operation is otherwise the same as that of the system of Fig. 2. Clearly, Fig. 1 can be modified in accordance with Fig. 3; and it goes Without saying that switch 29 can have as many fixed contacts as desired and that there may be a corresponding number of parallel paths, each including a condenser shunted by a leakage resistance.

It will be understood, of course, that the invention is not limited to the embodiments shown and described but contemplates such further modifications as fall within the scope of the appended claims.

I claim:

1. In combination, an electrical device, a holding circuit for said device including a contact which is operative in response to cnergization of said device to close said holding circuit, and to open said holding circuit in response to deenergization of said device, a path including said device in series with a condenser and a switch, but excluding said contact, and means in shunt to said condenser for discharging the same, said path being closed upon closure of said switch.

2. In combination, an electrical device, a holding circuit for said device including a contact which is operative in response to energization of said device to close said holding circuit, and to open said holding circuit in response to deenergization of said device, a plurality of paths, each including an individual condenser, in series with said device but excluding said contact, switching means for selectively closing. said paths individually, and means operative to discharge each of said condensers while the same is not included in a closed one of said paths.

3. In combination, an electrical device, a holding circuit for said device including said device in series with a contact and a source of current, said contact being operative in response to energization of said device to close. said holding circuit, and to open said holding circuit in response to deenergization of said device, a circuit including said device for initially energizing said device, and means for de-energizing said device, said means comprising a path including said device in series with a condenser and a switch, and

to an arrangement comprising, specifically, two

such paths, but may, in fact, be incorporated in a system comprising any number of such paths. It is rather obvious that the systems of Figs. 1 and 2 could be modified by eliminating either one of the two parallel paths l1, l8 and that such a shunting means for discharging said condenser, said path being closed upon closure of said switch.

4. In combination, an electrical device, a holding circuit for said device including said device in series with a contact and a source of current, said contact being operative in response to energization of said device to close said holding circuit, and to open said holding circuit in response to deenergization of said device, a circuit for initially energizing said device and includng sad device in series with a condenser and also in series with a switch and a source of current, said condenser being shunted by a discharge path, and means for de-energizing said device to effect 1 release of said contact and thereby open said holding circuit.

5. In combination, an electromagnet, a plurality of condensers, each shunted by a high resistance leakage path individual thereto, and switchingmeans operative to complete a series path through a winding of said electromagnet and rality of condensers, each shunted by a high resistance leakage path individual thereto, switching means operative to connect said condeners individually and sequentially in series with a winding of said electromagnet, and a holding circuit for maintaining said electromagnet energized following each energization thereof.

7. In combination, a circuit comprising a winding of an electromagnet and a source of current, two parallel branch paths, and switching means operative to connect said branch paths alternately and individually into said circuit in series with said winding and source of current, each of said branchpaths including a condenser individual thereto, each of said condensers being shunted by an individual leakage resistor, a holding circuit including said winding in series wth a holding contact and a source of current, said holding contact being operative to close said holding circuit in response to energization of said winding and to open said holding circuit in response to de-energization of said winding, and means for short-circuiting said winding to effect de-energization thereof.

8. In combination, a circuit comprising a winding of an electromagnet and a source of current, two parallel branch paths, and switching means operative to connect said branch paths alternately. and individually into said circuit in series with said winding and source of current, each of said branch paths including a condenser individual thereto, each of said condensers being shunted by an individual leakage resistor, a holding circuit including said winding in series with a holding contact and a source of current, said holding contact being operative to close said holding circuit in response to energization of said winding and to open said holding circuit in response to de-energization of said winding, and means for de-energizing said winding.

9. In combination, an electromagnet, a plurality of condensers, switching means operative to complete a series path through a winding of said electromagnet and each of said condensers individually and selectively, and means operative to discharge each of said condensers while the latter is not included in said series path.

10. In combination, an electrical device, a plurality of condensers, switching means operative to complete a series path through said device and each of said condensers individually and sequentially, means operative to discharge each of said condensers while the latter is not included in said series path, and a holding circuit for maintaining said device energized following each energization thereof.

11. In combination, an electrical device, a plurality of condensers, a source of current, switching means operative to complete a series circuit through said device and source and each of said condensers individually and sequentially, means operative to discharge each of said condensers while the latter is not included in said series circuit, a holding circuit for maintaining said device energized following each energization thereof, and means for thereafter releasing said holding circuit.

DAVID ELIAS SUNS'I'EIN. 

